Emerging evidence has underscored the potential usefulness of red blood cell distribution width (RDW) measurement in predicting the mortality and disease severity of COVID‐19. This study aimed to assess the association of the plasma RDW levels with adverse prognosis in COVID‐19 patients. A comprehensive literature search from inception to September 2020 was performed to harvest original studies reporting RDW on admission and clinical outcomes among patients hospitalized with COVID‐19. RDW levels were compared between cases (patients who died or developed more severe symptoms) and controls (patients who survived or developed less severe symptoms). A total of 14,866 subjects from 10 studies were included in the meta‐analysis. Higher levels of RDW were associated with adverse outcomes in COVID‐19 patients (mean differences = 0.72; 95% CI = 0.47–0.97; I2 = 89.51%). Deceased patients had higher levels of RDW compared to patients who survived (mean differences = 0.93; 95% CI = 0.63–1.23; I2 = 85.58%). Severely ill COVID‐19 patients showed higher levels of RDW, as opposed to patients classified to have milder symptoms (mean differences = 0.61; 95% CI = 0.28–0.94; I2 = 82.18%). Elevated RDW levels were associated with adverse outcomes in COVID‐19 patients. This finding warrants further research on whether RDW could be utilized as a simple and reliable biomarker for predicting COVID‐19 severity and whether RDW is mechanistically linked with COVID‐19 pathophysiology.

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Background: Betrixaban and rivaroxaban are the direct anticoagulants approved in the United States for extended venous thromboembolism (VTE) prophylaxis among acutely ill medical patients. The efficacy and safety in specific subgroups remain unclear. Methods: A meta-analysis of 3 randomized trials involving extended thromboprophylaxis with betrixaban or rivaroxaban versus enoxaparin for medically ill patients was performed to compare VTE (composite of asymptomatic proximal and symptomatic deep vein thrombosis, pulmonary embolism, or VTE-related death) and major bleeding in subgroups by baseline D-dimer, age, sex, and major medical illness on hospitalization. Risk difference (RD) was computed with the Mantel-Haenszel method by fitting a fixed-effect model. Heterogeneity of treatment effect across subgroups was examined using the nominal thresholds of P < 0.05 and I2 > 75%. Results: Compared with enoxaparin, extended betrixaban or rivaroxaban reduced VTE (RD = –1.51% [95% CI, –2.32% to –0.69%]; P = 0.0003) without excess major bleeding (RD = 0.12% [–0.05% to 0.29%]; P = 0.16). A significant effect modification was observed in the subgroups by D-dimer (P = 0.004) and age (P = 0.04). Patients with D-dimer >2× upper limit of normal (ULN) experienced a greater VTE reduction (RD = –2.39% [–3.57% to –1.21%]; P < 0.0001) than those with ≤2×ULN (RD = –0.26% [–1.08% to 0.56%]; P = 0.53). Similarly, patients aged ≥75 years had a greater VTE reduction (RD = –2.29% [–3.49% to –1.09%]; P = 0.0002) than those aged <75 years (RD = –0.63% [–1.70% to 0.44%]; P = 0.25). Treatment effect was consistent across the remaining subgroups. Conclusions: A more favorable efficacy and comparable safety outcome associated with extended betrixaban or rivaroxaban were observed among medical inpatients with D-dimer >2×ULN or aged ≥75 years. D-dimer and advanced age may assist in decision-making on pharmacological thromboprophylaxis for hospitalized medical patients.